Move stack_top code from cothread_create() to cothread_context_init(), since we only need to calculate it once.
Move stack_top code from cothread_create() to cothread_context_init(), since we only need to calculate it once.

Original commit message from CVS:
Move stack_top code from cothread_create() to cothread_context_init(),
since we only need to calculate it once.

justinjoy/gstreamer,centricular/gstreamer,collects/gstreamer,krichter722/gstreamer,lubosz/gstreamer,cablelabs/gstreamer,Lachann/gstreamer,Distrotech/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,shelsonjava/gstreamer,magcius/gstreamer,ylatuya/gstreamer,mparis/gstreamer,jpakkane/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,Lachann/gstreamer,lovebug356/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,ahmedammar/platform_external_gst_gstreamer,cfoch/gstreamer,Lachann/gstreamer,justinjoy/gstreamer,ensonic/gstreamer,mrchapp/gstreamer,mparis/gstreamer,justinjoy/gstreamer,Distrotech/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,magcius/gstreamer,collects/gstreamer,magcius/gstreamer,magcius/gstreamer,surround-io/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,centricular/gstreamer,lovebug356/gstreamer,cfoch/gstreamer,jpakkane/gstreamer,surround-io/gstreamer,lubosz/gstreamer,mrchapp/gstreamer,mrchapp/gstreamer,ylatuya/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,cfoch/gstreamer,drothlis/gstreamer,surround-io/gstreamer,drothlis/gstreamer,ensonic/gstreamer,ensonic/gstreamer,drothlis/gstreamer,ylatuya/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,magcius/gstreamer,collects/gstreamer,ylatuya/gstreamer,ahmedammar/platform_external_gst_gstreamer,Lachann/gstreamer,krieger-od/gstreamer,mrchapp/gstreamer,justinjoy/gstreamer,krieger-od/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,Distrotech/gstreamer,StreamUtils/gstreamer,ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,centricular/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,centricular/gstreamer,ylatuya/gstreamer,mparis/gstreamer,lubosz/gstreamer,cablelabs/gstreamer,jpxiong/gstreamer,jpxiong/gstreamer,lubosz/gstreamer,collects/gstreamer,Distrotech/gstreamer,cablelabs/gstreamer,collects/gstreamer,surround-io/gstreamer,jpxiong/gstreamer,Distrotech/gstreamer,krichter722/gstreamer,ahmedammar/platform_external_gst_gstreamer,StreamUtils/gstreamer,mrchapp/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,drothlis/gstreamer,Lachann/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,ahmedammar/platform_external_gst_gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,lubosz/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,surround-io/gstreamer,drothlis/gstreamer